Core A, Radiophysics, will provide 4 support areas to the Program Project. These include (1) the provision of animal and clinical imaging, (2) modeling of antibody pharmacokinetics using ADAPT II and SAAM software, (3) estimation of absorbed radiation doses using our patented RTDS system, and (4) counting quality assurance in single photon and PET radioimaging and radioassays. Images provide a guide to disease extent, spread and surgical treatment. In addition, they are the primary input into the estimation of organ and tumor uptake in the patient. Modeling is needed since we require biodistributions of 111In-Mabs to stand in for the subsequent 90Y-Mab; thus, we use the image data as the modeler's input to predict the therapy application's biodistribution in patients. We will compare model predictions of organ and tumor uptake with surgical samples. Radiation dose is estimated using the model's individual organ uptake time-activity integrals. Such dose estimates will be compared with clinical data such as blood cell levels. Finally, counting experiment quality assurance will be determined from Core A. The Radiophysics Core will continue to provide support to Dr. Wong (Project 5), Dr. Gambhir (Project 6), Dr. Wu (Project 2) and Dr. Shively (Project 1). We will collaborate with Dr. Gambhir and Dr. Dahlbom at UCLA to optimize the PET imaging acquisition and reconstruction. These studies will include protein and other molecules labeled with 18F, 64Cu and 124I radionuclides. We will maintain our close association with Dr. Raubitschek (Core B and Project 5) as well as Dr. Ikle (Core E, Biostatistics). Additionally, Core A will provide imaging and dose estimation service for the animal studies (Dr. Wong, Core D).